Non-contact electrode basket catheters with irrigation

ABSTRACT

Catheter systems and methods are disclosed. An exemplary catheter includes an outer tubing housing and an inner fluid delivery tubing, the inner fluid delivery tubing having at least one fluid delivery port. The catheter also includes a deployment member movable axially within the inner fluid delivery tubing. A plurality of splines are each connected at a proximal end to the outer tubing and at a distal end to deployment member. A seal is provided between the outer tubing and the inner fluid delivery tubing. A gasket is provided between the deployment member and the inner fluid delivery tubing. Both the seal and the gasket are configured to prevent blood or other fluid from ingressing into the outer tubing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/345,606, filed 29 Dec. 2008, (the '606 application). The '606application is hereby incorporated by reference as though fully setforth herein.

BACKGROUND OF THE INVENTION

a. Field of the Invention

The instant invention is directed toward non-contact electrode basketcatheters with irrigation for delivering a fluid (e.g., ananticoagulant) during a medical procedure. In particular, thenon-contact electrode basket catheter of the present invention may beused to deliver the fluid between splines of the basket catheter duringmedical procedures.

b. Background Art

Normal heart rhythm is between 60 and 100 beats per minute. Tachycardiais a fast heart rate (usually over 100 beats per minute) caused bydisease or injury. Tachycardias may begin in the upper chambers of theheart (the atria) or the lower chambers of the heart (the ventricles).Some tachycardias are harmless, but other tachycardias are lifethreatening. Tachycardias can deteriorate to fibrillation, a disorder inwhich, the heart does not move enough blood to meet the needs of thebody.

Atrial fibrillation (AF) is the most common abnormal heart rhythm. It isa very fast, uncontrolled heart rhythm that occurs when the upperchambers of the heart (the atria) try to beat so fast (between 350 and600 times per minute) that they only quiver. Ventricular fibrillation(VF) occurs when the lower chambers of the heart (the ventricles)produce fast and erratic electrical impulses that fail to inducesynchronous mechanical contraction, such that oxygenated blood is notcirculated through the body. Fibrillation in the ventricles is alife-threatening arrhythmia demanding immediate treatment.

Before a tachycardia deteriorates to fibrillation, various proceduresmay be used to treat the heart tissue and reduce or altogether eliminatethe occurrence of fibrillations. It is well known that treatmentbenefits may be gained by creating lesions in the heart tissue, whichchange the electrical properties of the tissue, if the depth andlocation can be controlled. For example, cardiac ablation techniques areknown for forming lesions at specific locations in cardiac tissue tolessen or eliminate undesirable atrial fibrillations. Likewise, biologicand chemical agents may be delivered into infracted tissue in the lowerchambers of the heart (the ventricles) to promote angiogenesis for thetreatment of Ventricular Tachycardia (VT). Other procedures are alsoknown for treating these and other ailments. Use of a particularprocedure depends at least to some extent on the desired treatment, andmay also depend on other considerations, such as tissue characteristics.

A basket catheter may be employed for ablation and other procedures(e.g., mapping) on the heart. The catheter system may include an outercatheter shaft also referred to as a “guiding introducer”. The guidingintroducer defines at least one lumen or longitudinal channel. Adelivery sheath is fitted through the guiding introducer. Topre-position the sheath at the appropriate location in the heart, adilator is first fitted through the sheath. In an example of a procedurewithin the left atrium, the sheath and the dilator are first inserted inthe femoral vein in the right leg. The sheath and dilator are thenmaneuvered up to the inferior vena cava and into the right atrium. Inwhat is typically referred to as a transseptal approach, the dilator ispressed through the interatrial septum between the right and left atria.A dilator needle may be used here to make an opening for the dilator topass through. The dilator expands the opening sufficiently so that thesheath may then be pressed through the opening to gain access to theleft atrium and the pulmonary veins. With the sheath in position, thedilator is removed and the basket catheter, needle, or other device(depending on the procedure) is fed into the lumen of the sheath andpushed along the sheath into the left atrium. When positioned in theleft atrium, various mapping and/or ablation procedures, such as theablation procedures described above, may be performed within the heart.

Several difficulties may be encountered, however, during these medicalprocedures using some existing basket catheters. For example, a slowingor stoppage of the flow blood may occur between the splines of thebasket catheter, e.g., where the splines are attached to the catheter.This slowing or stoppage of the flow of blood may result in blood clotformation and may possibly lead to a thrombus. A thrombus may decreaseblood flow or even completely cut off blood flow, resulting in heartattack or stroke. Indeed, the risk of thrombus formation in the heartcontinues to exist even after the basket catheter has been removedfollowing the medical procedure.

Thus, there remains a need for irrigation of a basket catheter during amedical procedure.

BRIEF SUMMARY OF THE INVENTION

It is desirable to be able to deliver an anticoagulant such as aheparinized saline solution or other fluid in a basket catheter duringvarious medical procedures, e.g., to reduce the risk of blood clot orthrombus formation. One effective way to prevent blood coagulation andthrombus formation is to irrigate the electrode with heparinized saline.It is further desirable to be able to seal a distal end of the catheterto prevent blood ingress into the catheter shaft during the medicalprocedure.

These and other objectives can be accomplished by the catheter systemsand methods disclosed herein by providing a non-contact electrode basketcatheter with irrigation. A seal may also be configured in the cathetersystem to reduce or altogether prevent blood ingress into the cathetershaft.

An exemplary non-contact electrode basket catheter with irrigationincludes an outer tubing housing an inner fluid delivery tubing, theinner fluid delivery tubing having at least one fluid delivery port. Thecatheter also includes a deployment member movable axially within theinner fluid delivery tubing. A plurality of splines are each connectedat a proximal end to the outer tubing and at a distal end to deploymentmember. The plurality of splines expand when the deployment member ismoved in a first direction, and the plurality of splines collapse whenthe deployment member is moved in a second direction, the firstdirection being opposite the second direction. A seal is providedbetween the outer tubing and the inner fluid delivery tubing. A gasketis provided between the deployment member and the inner fluid deliverytubing. Both the seal and the gasket are configured to prevent blood orother fluid from ingressing into the outer tubing.

An exemplary catheter system comprises a delivery sheath, and anon-contact electrode basket catheter insertable through the deliveryshaft. The basket catheter includes a plurality of splines operable tobe moved by a deployment member between a deployed position and anundeployed position. The basket catheter also includes a fluid deliverytube housed within the basket catheter. The fluid delivery tube has atleast one fluid delivery port for irrigating within the basket catheterbetween the plurality of splines to reduce clotting or thrombusformation. The basket catheter also includes a seal fixedly providedbetween the fluid delivery tube and an outer tube of the basketcatheter. The seal preventing blood or fluid ingress into the outertubing.

Another exemplary non-contact electrode basket catheter system withirrigation comprises a catheter shaft, and a basket catheter insertablethrough the catheter shaft. The basket catheter includes a fluiddelivery tubing provided within an outer tubing, and a plurality ofsplines connected to the outer tubing and on one end and to a deploymentmember on an opposite end. The deployment member is operable to move thesplines between an expanded configuration and a collapsed configuration.The basket catheter also includes fluid delivery means for irrigatingwithin the basket catheter between the plurality of splines to reduceclotting or thrombus formation. The basket catheter also includessealing means for stopping blood or fluid from ingressing into thecatheter shaft.

An exemplary method comprises the steps of moving a deployment memberaxially within an inner fluid delivery tubing in a first direction toexpand a plurality of splines of a non-contact electrode basketcatheter, and moving the deployment member axially within the innerfluid delivery tubing in a second direction to collapse the plurality ofsplines. The method also comprises the steps of irrigating between thesplines of the non-contact electrode basket catheter, and preventingfluid ingress into a catheter shaft.

The foregoing and other aspects, features, details, utilities, andadvantages of the present invention will be apparent from reading thefollowing description and claims, and from reviewing the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an exemplary embodiment of a cathetersystem.

FIG. 2 a-b are isometric views of an exemplary embodiment of anon-contact electrode basket catheter with irrigation which may beimplemented with the catheter system in FIG. 1 , wherein (a) shows thebasket portion of the catheter in a collapsed configuration, and (b)shows the basket portion of the catheter in an expanded configuration.

FIG. 3 a is a cutaway isometric view of a distal portion of the basketcatheter showing an exemplary configuration of distal fluid deliveryports. FIG. 3 b is a close-up isometric view of a distal portion of thebasket catheter showing an alternative configuration of the distal fluiddelivery ports.

FIG. 4 is an isometric view of an exemplary basket catheter without thesplines.

FIG. 5 a-b are isometric views of the basket catheter of FIG. 4 with thebase layer of the splines attached to show electrodes and electrodetraces for the basket catheter. In FIG. 5 b , the electrode traces areshown as the electrode traces may be fit into channels formed withininterstitial spaces of the catheter shaft.

FIG. 6 is an isometric view of the basket catheter of FIG. 4 with anouter layer of the splines shown covering the electrodes and electrodetraces in FIG. 5 a.

DETAILED DESCRIPTION OF THE INVENTION

Several embodiments of a catheter system according to the presentinvention are depicted in the figures as the catheter system may be usedfor irrigation delivery of an anticoagulant, such as heparinized saline,or other fluid in a basket catheter during a medical procedure. In anexemplary embodiment, the basket catheter is a non-contact electrodebasket catheter which may be used for ablation or other procedures(e.g., mapping). As described further below, the catheter of the presentinvention provides a number of advantages, including, for example,facilitating irrigation during the medical procedure to reduce bloodclot or thrombus formation without blood ingress into the cathetershaft. The catheter system may also be used in difficult environments,such as in a beating heart.

Before continuing, it is noted that other components typical of cathetersystems which are conventionally implemented for these and other medicalprocedures are not shown or described herein for purposes of brevity.Such components may nevertheless also be provided as part of, or for usewith, the catheter system. For example, catheter systems commonlyinclude or are used in conjunction with an ECG recording system, and/orvarious input and output devices. Such components are well understood inthe medical devices arts and therefore further explanation is notnecessary for a complete understanding of the invention.

FIG. 1 is an isometric view of an exemplary embodiment of a cathetersystem 10. The catheter system 10 may include a handle 12 and connector14 at the base or proximal end 15. An outer catheter shaft also referredto as a “guiding introducer” 16 having a tubular body is connected tothe connector 14 on the proximal end (e.g., illustrated by referencenumber 15 in FIG. 1 ) of the catheter system 10. As used herein andcommonly used in the art, the term “proximal” is used generally to referto components or portions of the catheter system 10, such as the handle12 and connector 14 that are located or generally orientated away fromor opposite the heart or other target tissue when the catheter system 10is in use. On the other hand, the term “distal” (e.g., illustrated inFIG. 1 by reference number 17) is used generally to refer to componentslocated or generally orientated toward the heart or other target tissuewhen the catheter system 10 is in use.

The guiding introducer 16 defines at least one lumen or longitudinalchannel. A delivery sheath 18 is fitted through the guiding introducer16. In one implementation, the guiding introducer 16 and sheath 18 arefabricated from a flexible resilient material, and are preferablyfabricated of materials suitable for use in humans, such asnonconductive polymers. Suitable polymers include those well known inthe art, such as polyurethanes, polyether-block amides, polyolefins,nylons, polytetrafluoroethylene, polyvinylidene fluoride, andfluorinated ethylene propylene polymers, and other conventionalmaterials. Some portions of the guiding introducer 16 and/or sheath 18may be braided for enhanced stiffness.

In exemplary implementations, the guiding introducer 16 and sheath 18are each about two to four feet long, so that they may extend from theleft atrium through the body and out of the femoral vein in the rightleg and be connected with various catheter devices such as the connector14, one or more fluid control valves 1-3, and the like.

The sheath 18 is configured to receive and guide a device for carryingout the procedure (e.g., the basket catheter 25 shown in FIG. 2 a-b )within the lumen to the target tissue. The sheath 18 is pre-positionedin the appropriate location in the heart prior to introduce a device. Topre-position the sheath 18 at the appropriate location in the heart, adilator 20 is first fitted through the sheath 18. In an example of aprocedure within the left atrium, the sheath 18 and the dilator 20 arefirst inserted in the femoral vein in the right leg. The sheath 18 anddilator 20 are then maneuvered up to the inferior vena cava and into theright atrium. In what is typically referred to as a transseptalapproach, the dilator 20 is pressed through the interatrial septumbetween the right and left atria. A needle may be used here to make anopening for the dilator 20 to pass through. The dilator expands theopening sufficiently so that the sheath 18 may then be pressed throughthe opening to gain access to the left atrium and the pulmonary veins.With the sheath 18 in position, the dilator 20 is removed and the basketcatheter 25 (FIG. 2 a-b ) may be fed into the lumen of the sheath 18 andpushed along the sheath 18 into the left atrium. When positioned in theleft atrium, various procedures (e.g., ablation and mapping procedures)may be performed within the heart tissue using the basket catheter.

Once the sheath 18 is pre-positioned in the appropriate location in theheart, the basket catheter 25 may be at least partially extended outfrom the lumen at the distal end 17 of the sheath 18 (e.g., in thedirection illustrated by arrow 22 a) so that the basket catheter 25 maybe positioned adjacent the target tissue, and then expanded asillustrated in FIG. 2 b for the medical procedure. The basket catheter25 may also be collapsed as illustrated in FIG. 2 a , and then retracted(e.g., in the direction of arrow 22 b) before removing the cathetersystem 10 from the body.

Before continuing, it is noted that the catheter system 10 has beendescribed as it may be inserted for procedures in the left atrium in thevicinity of or within the pulmonary veins of the heart. The cathetersystem 10, however, is not limited to such procedures, and may be usedfor procedures involving other target tissue in other areas of the heartand body.

The following discussion will now be with reference to the basketcatheter 25 shown in FIG. 2 a-b . FIG. 2 a-b are isometric views of anexemplary embodiment of a non-contact electrode basket catheter 25 withirrigation which may be implemented with the catheter system 10 in FIG.1 , wherein (a) shows the basket portion of the catheter in a collapsedconfiguration, and (b) shows the basket portion of the catheter in anexpanded configuration.

In these figures, an exemplary basket catheter 25 is shown as it mayinclude an outer tubing 30 housing an inner fluid delivery tubing 32 anda deployment member 31. The inner fluid delivery tubing 32 includes atleast one fluid delivery port 34 within the splines 36 of basketcatheter 25. It is noted that two fluid delivery ports 34 a-b andsplines 36 a-b are visible in FIG. 2 a . In FIG. 2 b , splines 36 a-fare visible in FIG. 2 b . However, the basket cathether 25 is notlimited to any particular configuration (including number of splines ornumber or placement of ports), as will be readily understood by thosehaving ordinary skill in the art after becoming familiar with theteachings herein.

Each spline 36 is connected at the proximal end of the splines 36 to theouter tubing 30, and each spline 36 is connected at the opposite ordistal end of the splines 36 to the deployment member 31. The deploymentmember 31 is operable to be moved in a first direction (e.g., in thedirection of arrow 38 a) relative to the outer tubing 30 to expand thesplines 36 to a deployed position, as shown in FIG. 2 b . The deploymentmember 31 is also operable to be moved in a second direction (e.g., inthe direction of arrow 38 b in FIG. 2 b ) relative to the outer tubing30 to collapse the splines 36 to an undeployed position, as shown inFIG. 2 a.

The deployment member 31 may include a pull wire. For example. Thedeployment member 31 may be a solid stainless steel or Nitinol wire.Alternatively, the deployment member 31 may be a hollow tubing (orconfigured to house tubing). An embodiment wherein the deployment member31 is a fluid delivery tubing is described in more detail below withreference to FIG. 3 b . In either case, however, the deployment member31 should be manufactured to be sufficiently stiff such that thedeployment member 31 can be operated remotely (e.g., outside of thepatient's body) to be moved in the directions illustrated by arrow 38 aand 38 b in FIG. 2 a-b to expand and contract the splines 36.

In any event, the basket catheter 25 may be inserted into the cathetershaft (e.g., sheath 18) in its undeployed position as shown in FIG. 2 afor placement in the patient's body (e.g., within a heart chamber). Thebasket catheter 25 may then be expanded to its deployed position asshown in FIG. 2 b for a medical procedure within the patient's body.Following the procedure, the basket catheter 25 may again be collapsedto its undeployed position so that the basket catheter 25 may bewithdrawn through the delivery sheath 18 of the catheter 10.

In an exemplary embodiment, the deployment member 31 may be connected toport 5 on the handle 12 of catheter system 10 (in FIG. 1 ). A handleportion may be operatively associated with the deployment member 31 insuch a manner that movement of the handle is directly translated intomovement of the deployment member 31. Other embodiments of deploymentsystems are also contemplated and are not limited to the specificimplementation described above. For example, the handle may bespring-loaded (not shown). The spring acts to bias the handle in a fullyextended or pulled back position. Accordingly, a force must be appliedto the handle in order to release the handle, and hence return thedeployment member 31 toward its starting position. This may help ensurethat the user does not leave the splines 36 of the basket in theexpanded position as shown in FIG. 2 b when attempting to remove thebasket catheter 25 from the patient's body. This may also help ensurethat the basket catheter 25 is not accidentally deployed duringplacement in the patient's body (doing so could cause unintended damageto tissue or other parts of the patient's body). Still other embodimentsare also contemplated. For example, different mechanisms for controllingthe distance the deployment member 31 can travel may also beimplemented.

FIG. 3 a is cut-away isometric view of a distal portion of the basketcatheter 25 showing an exemplary configuration of distal fluid deliveryports 34. Fluid delivery is illustrated by arrows 37 a as the fluid maybe delivered from ports 34 a at the distal end of the fluid deliverytube 32, and by arrows 37 b from ports 34 a as the fluid may bedelivered from ports 34 b at the proximal end of the fluid delivery tube32.

A seal 40 is also visible in FIG. 3 a . The seal 40 may be manufacturedof any suitable material. Seal 40 is provided between the inner fluiddelivery tube 32 and the outer tubing 30. For example, the seal 40 maybe molded or bonded to the inner fluid delivery tube 32 and/or the outertubing 30. In an exemplary embodiment, the seal 40 may be oversized,e.g., having an inner diameter which is smaller than the outer diameterof the inner fluid delivery tubing 32 and having an outer diameter whichis larger than the inner diameter of the outer tubing 30. The specificdiameters may vary depending on a number of design considerations, suchas, the diameters of the inner fluid delivery tubing 32 and outer tubing30, or other components of the catheter 10. Sizing the diameters in sucha manner enables the seal 40 to provide a snug fit between the tubing 30and 32 to prevent blood or other fluid from ingressing back within thecatheter shaft.

It should also be noted that blood or other fluid may also be kept fromingressing back within the catheter shaft through the fluid deliveryports 34 a and 34 b by continuous fluid delivery at a positive pressurethrough these ports. In exemplary embodiments, it has been determinedthat fluid flow rates of 1 mL/m to 5 mL/m provide sufficient positivepressure so as to prevent blood or other fluid from ingressing throughthe fluid delivery ports 34 a and 34 b. However, these are merelyexemplary, and specific flow rates may be determined for any of a widevariety of fluid delivery port configurations by those having ordinarlyskill in the art after becoming familiar with the teachings herein.

A gasket 41 is visible in FIGS. 2 a and 2 b , and serves a similarpurpose to the seal 40 in FIG. 3 a . Specifically, the gasket 41 enablesthe deployment member 31 to be moved in the directions illustrated byarrows 38 a and 38 b to expand and collapse the splines 36, whilepreventing blood or other fluid from ingressing back within the cathetershaft.

In an exemplary embodiment, the seal 40 and gasket 41 may bemanufactured of an elastic polymer. However, the seal 40 and gasket 41may be manufactured of any other suitable material as well, includingbut not limited to rubber, plastic, or metal.

FIG. 3 b is a close-up isometric view of a distal portion 42 of thebasket catheter 25 showing an alternative configuration of the distalfluid delivery ports 34 a′. In this embodiment, the deployment member 31may be a tubing (or house a tubing) fluidically connected on one end toa fluid source, and on the other end to the distal fluid delivery ports34 a′ provided on the deployment member 31. The distal fluid deliveryports 34 a′ may be fluidically connected to the same fluid source as theinner fluid delivery tubing 32 or to a separate fluid source. In anycase, such an embodiment enables fluid delivery closer to the distalportion 42 of the basket catheter 25 even when the splines 36 are in anundeployed position (e.g., FIG. 2 a ).

Before continuing, it is noted that any configuration of the distalfluid delivery ports 34 a′ may be implemented and is not limited to theconfiguration (or number of ports) shown in FIG. 3 b . Likewise, distalfluid delivery ports 34 a′ may be implemented with (in addition to) orwithout the fluid delivery ports 34 a on inner fluid delivery tubing 32.

Although the fluid delivery mechanisms and irrigation systems andmethods described above may be implemented with any suitable basketcatheter 25, exemplary manufacture of a preferred embodiment of anon-contact electrode basket catheter will now be described withreference to FIG. 4-6 . FIG. 4 is an isometric view of an exemplarybasket catheter 25 without the splines 36. In FIG. 4 , the deploymentmember 31 is shown fitted within fluid delivery tubing 32. Thedeployment member 31 may be a Nitinol wire which may be pre-bent to thedesired shape. The deployment member 31 is configured for axial movementrelative to the fluid delivery tubing 32. The fluid delivery tubing 32is in turn fitted within outer tube 30. Outer tube 30 may comprise aninner shaft 50 which provides structural support and also has formedtherein channels or interstitial spaces 51 for electrical wiring and/orfluid tubing (see, e.g., FIG. 5 b ). Outer tube 30 may also comprise abraided section 52 to contain the electrical wiring and/or fluid tubingwithin the interstitial spaces 51, and a cover 54.

It should be noted that although the section of the basket catheter 25shown in FIG. 4 is depicted as having a circular cross-section, thecross-section may intentionally or unintentionally have a wide varietyof cross-sectional configurations, and need not be circular. Forexample, manufacturing irregularities may result in differentcross-sectional configurations. Or for example, differentcross-sectional configurations (e.g., hexagonal, octagonal) may beintentionally selected to achieve desired properties. The particularconfiguration used will depend at least to some extent on designconsiderations. Exemplary design considerations may include, but are notlimited to, the material and desired structural properties, the length,shape, and cross-sectional area. And of course, the design parametersmay be different for various procedures or physician preferences.

FIG. 5 a-b are isometric views of the basket catheter 25 of FIG. 4 withthe base layer 56 of the splines 36 attached to show electrodes 58 andelectrode traces 59 for the basket catheter. In an exemplary embodiment,the splines 36 are formed from sheets. The sheets can be formed of asuitable flexible material such as plastic (e.g., polyimide).Plastic-coated stainless steel sheets may also be used to provideadditional rigidity. In any event, the sheets are formed with aplurality of longitudinally extending slits spaced transversely of thesheet. Longitudinally spaced apart electrodes 58 and correspondingelectrode traces 59 are provided on the splines 36.

The splines 36 may be formed by rolling the sheets onto a mandrel andthen bonding the distal ends to the distal end 43 of the deploymentmember 31, and on the proximal end to the outer tube 30, e.g., withinthe channels 51. The sheets form a flexible circuit and may include goldplated electrode tabs 58.

In FIG. 5 b , the electrode traces are shown as the electrode traces maybe bonded so that the electrode traces 59 fit through the channels 51 ofthe outer tube 32. The traces 59 may then be connected to electricalwiring and extend through the lumen of the catheter system 10. Theelectrical wiring may convey electrical signals between the electrodes58 and one or more control system (not shown). For example, theelectrical signals may be used to control output of ablation electrodes,or for processing input from mapping electrodes for viewing by the user,(e.g., on an electrical monitoring device).

It is also noted that the fluid delivery tubing 32 may also extendthrough a channel 60 formed through the center of the outer tube 30. Ofcourse other designs for the inner shaft 50 of the outer tube 30 mayalso be implemented, as will be readily understood by those havingordinary skill in the art after becoming familiar with the teachingsherein. For example the channel 60 need not maintain the inner fluiddelivery tubing 32 in the center of outer tube 30. It is only desiredthat the inner fluid delivery tubing 32 be maintained in a substantiallyconstant position within the diameter of the outer tube 30 foruninterrupted flow of the fluid during the procedure.

FIG. 6 is an isometric view of the basket catheter 25 of FIG. 4 with anouter layer 62 of the splines 36 shown covering the electrodes 58 andelectrode traces 59 in FIG. 5 a . Accordingly, the splines 36 may form anon-contact electrode basket catheter. The outer layer 62 may also beused as an additional stiffener to protect the flexible circuit portionof the splines 36.

It is noted that the various embodiments of catheter system 10 describedabove may also be implemented with a wide variety of different sensingmeans. These sensing means enable the catheter system 10 to beimplemented for tissue contact assessment during the procedures,including contact with the tissue. For example, the catheter system 10may include one or more piezoelectric sensor embedded in the splines 36.The piezoelectric sensor generates electric signals in response tostresses caused by contact with the tissue. Radiopaque sensors may alsobe used. Still other exemplary sensing devices may include pressure,thermistor, thermocouple, or ultrasound sensors. In addition, more thanone sensor or type of sensor may be implemented to provide additionalfeedback to the user. In any event, when the splines 36 are positionedin contact with and/or moved over a tissue, the sensors may beimplemented to generate an electrical signal corresponding to stresscaused by this contact and/or movement for tissue contact assessment.

It is noted that any suitable analog and/or digital device may also beimplemented for outputting data of electrical signals generated by thesensor(s) to a user. In addition, the electrical signals may be furthercharacterized using a suitable processing device such as, but notlimited to, a desktop or laptop computer. Such processing device may beimplemented to receive the voltage signal generated by the contactassessment sensor(s) and convert it to a corresponding contact conditionand output for the user, e.g., at a display device, an audio signal, ortactile feedback or vibrations on the handle of the catheter. In anyevent, circuitry for conveying output of the piezoelectric sensor to auser in one form or another may be readily provided by those havingordinary skill in the electronics arts after becoming familiar with theteachings herein.

Although several embodiments of this invention have been described abovewith a certain degree of particularity, those skilled in the art couldmake numerous alterations to the disclosed embodiments without departingfrom the spirit or scope of this invention. References are only used foridentification purposes to aid the reader's understanding of the presentinvention, and do not create limitations as to the position,orientation, or use of the invention. In addition, various combinationsof the embodiments shown are also contemplated even if not particularlydescribed. Changes in detail or structure, such as but not limited tocombinations of various aspects of the disclosed embodiments, may bemade without departing from the spirit of the invention as defined inthe appended claims.

What is claimed is:
 1. A catheter, comprising: an outer tubing thatforms an outer surface of the catheter, wherein the outer tubingcomprises an outer cover and an inner shaft disposed within the outercover, wherein the inner shaft comprises a plurality of inner shaftchannels that extend along a length of the inner shaft; and a pluralityof splines configured to deploy from an undeployed configuration to anexpanded configuration, wherein a proximal end of each of the pluralityof splines is connected to a distal end of the outer tubing and isdisposed within a respective one of the plurality of inner shaftchannels to prevent relative movement between the proximal end of eachof the plurality of splines and the distal end of the outer tubing,wherein each of the plurality of splines comprises a flexible circuitthat extends along a length of the spline, electrodes that aredistributed along the spline, and an outer layer that covers theelectrodes to prevent direct contact between the electrodes andmyocardial tissue within a cardiac muscle during at least one of atherapy and diagnostic procedure, wherein the outer layer is configuredto structurally stiffen the spline, wherein the catheter is configuredto be inserted into and advanced through a lumen of a separateintroducer sheath.
 2. The catheter of claim 1, wherein the electrodesare configured for use in conducting one or more of: anatomy mapping,electrophysiological mapping, temperature measuring, cardiac pacing, ormyocardial tissue ablation.
 3. The catheter of claim 2, wherein theelectrodes comprise gold plated electrodes.
 4. The catheter of claim 1,further comprising electrical leads that extend through at least one ofthe plurality of inner shaft channels and the outer tubing, wherein theelectrical leads communicatively couple at least a plurality ofelectrodes to controller circuitry.
 5. The catheter of claim 1, furthercomprising an inner fluid delivery tubing within the outer tubing, and adeployment member axially movable within the inner fluid deliverytubing; wherein: a distal end of the deployment member is coupled to adistal end of the plurality of splines; and the plurality of splines isconfigured to expand axially outward in response to movement of thedeployment member in a first direction, and collapse axially inward inresponse to movement of the deployment member in a second direction, thesecond direction being opposite the first direction.
 6. The catheter ofclaim 1, further comprising: an inner fluid delivery tubing within theouter tubing; a deployment member; a seal disposed between the outertubing and the inner fluid delivery tubing; and a gasket disposed at anend of the inner fluid delivery tubing between the deployment member andthe inner fluid delivery tubing, wherein both the seal and the gasketare configured to prevent blood or other fluid from ingressing into theouter tubing and the inner fluid delivery tubing.
 7. The catheter ofclaim 6, wherein the seal is maintained in a fixed position relative tothe outer tubing and the inner fluid delivery tubing.
 8. The catheter ofclaim 6, wherein the seal has an inner diameter smaller than an outerdiameter of the inner fluid delivery tubing, and wherein the seal has anouter diameter larger than an inner diameter of the outer tubing.
 9. Thecatheter of claim 6, wherein: the deployment member is axially movablewithin the inner fluid delivery tubing; a distal end of the deploymentmember connected to each of the plurality of splines; and the deploymentmember extends through the gasket and is configured to be moveablethrough the gasket to expand and collapse the plurality of splines. 10.The catheter of claim 1, further comprising an inner fluid deliverytubing and a deployment member, wherein the deployment member extendswithin the inner fluid delivery tubing.
 11. The catheter of claim 1,wherein distal ends of the plurality of splines are anchored to oneanother, and proximal ends of the plurality of splines are anchored bythe outer tubing, thereby forming an orb shape as the plurality ofsplines are deployed in the expanded configuration.
 12. The catheter ofclaim 1, wherein the proximal end of each of the plurality of splines isdirectly connected to the distal end of the outer tubing.
 13. A cathetercomprising: a catheter shaft that forms an outer surface of thecatheter, wherein the catheter shaft comprises an outer cover and aninner shaft that extends within the outer cover, wherein the inner shaftcomprises a plurality of inner shaft channels that extend along a lengthof the inner shaft; an expandable structure coupled to a distal end ofthe catheter shaft, wherein the expandable structure comprises aplurality of splines, wherein a proximal end of each of the plurality ofsplines is connected to a distal end of the catheter shaft and isdisposed within a respective one of the plurality of inner shaftchannels to prevent relative movement between the proximal end of eachof the plurality of splines and the distal end of the catheter shaft,wherein each of the plurality of splines comprises a flexible circuitthat extends along a length of the spline, electrodes that aredistributed along the spline, and an outer layer that covers theelectrodes, wherein the outer layer is configured to prevent directcontact between the electrodes and tissue during at least one of atherapy and diagnostic procedure; an inner deliver tubing comprising aplurality of fluid delivery ports, wherein the plurality of fluiddelivery ports is configured to direct irrigation fluid toward theexpandable structure; a fluid delivery lumen extending along a length ofthe catheter shaft and coupled to the plurality of fluid delivery ports,wherein the fluid delivery lumen is configured to distribute fluid froma reservoir disposed at a proximal end of the catheter shaft to theplurality of fluid delivery ports; and a deployment member that extendswithin the fluid delivery lumen, wherein a distal end of the deploymentmember is connected to a distal end of each of the plurality of splines,wherein the deployment member is axially movable within the cathetershaft to reconfigure the plurality of splines between an undeployedconfiguration and an expanded configuration, wherein the catheter isconfigured to be inserted into and advanced through a lumen of aseparate introducer sheath.
 14. The catheter of claim 13, wherein theelectrodes are configured to conduct one or more of: anatomy mapping,electrophysiological mapping, temperature measuring, cardiac pacing, ormyocardial tissue ablation.
 15. The catheter of claim 14, wherein theouter layer is configured to structurally stiffen the-expandablestructure in the expanded configuration.
 16. The catheter of claim 14,wherein the electrodes comprise gold plated electrodes.
 17. The catheterof claim 13, further comprising a handle and electrical leads, whereinthe electrical leads extend through at least one of the plurality ofinner shaft channels and the catheter shaft, wherein the electricalleads communicatively couple the electrodes to the handle.
 18. Thecatheter of claim 13, wherein the plurality of fluid delivery ports iscircumferentially disposed around the fluid delivery lumen.
 19. Thecatheter of claim 13, wherein the electrodes are configured-for use inconducting one or more of: anatomy mapping, electrophysiologicalmapping, temperature measuring, cardiac pacing, or myocardial tissueablation.
 20. The catheter of claim 13, wherein the proximal end of eachof the plurality of splines is directly connected to the distal end ofthe catheter shaft.